In a space vehicle, it is often necessary to make attitude corrections thereof about any one or a combination of three mutually orthogonal axes and for this purpose a pair of thrusters for producing relative opposite moments about each of the three axes are utilized. The monopropellant or bipropellant systems for fueling the thrusters is required to be valved thereby to control angular motions about each of the three axes. Such space vehicles are limited in power supply and it is therefore desirable that the power required to operate the various valving means consume as little power as is possible.